P0125 Code, No resolve so far...

[JBAirborne]

Evening everyone, I'm having a bit of an issue with my 95 GST.
I'm throwing a P0125 and I'm frankly out of ideas, almost.
I've changed the stat, it's a 180 like it calls for. Both sensors on the
stat housing were replaced afterwards, and I even went so far as
to replace the upstream O2 because my coworker said he had a GSX
throw the same code and it stopped after replacing the upstream...

I can clear the code and within 25 to 35 miles it throws it again,
now I'm just lost to it's actual solution and I do mechanics for a living,
if that's what you call us in the army ;P .

One odd thing I noticed was that my Rad Fan never shuts off from startup,
I can't seem to locate the switch that controls it in the engine bay. But I'm
fairly certain the relays would be ok if the fan is actually engaging correct?

Anyway, if anyone could help I'd really appreciate it. 14MPG is killing me
for in town/to work driving. .

 

[doctor_shock10]

that code also pops up cause you have low coolant levels so start by checking that.
it could also pop up do to:
1) leaking or stuck open sat
2)faulty temp sensor(which you said youve changed)
3)or insufficient warm up time.

 

[JBAirborne]

Well the stat is functioning properly, tested that.
Coolant levels are topped off completely, can't bleed anymore air.
Sensors are good, warm up time? How long should I allow my car to warm up?

 

[doctor_shock10]

honestly ive started my car up in 30 degree weather and left i just didnt beat on it so i dont really believe in that ya know? man im lost with answers if youve checked my other answers. sorry but good luck let me know what it was when you fix it.

mabye an ecu going bad but thats just a guess.

 

[Guzman08]

is the coolant temperature sensor connected properly? maybe u will have to replace that. around $23 at autozone

 

[tenn-gsx]

Check the wiring between the sensor and the ECU.

 

[black_gst]

I just had something like this happen to me.. it was the large temp sensor that sends signal to the ecu. i know you said you replaced it. but my fan would stay on non stop and what had happened is that one of the wires broke on that temp sensor. the car also ran like crap and pig rich because if a wire is broken it will read -70* to the ecu... i have dsmlink so i figured it out right away

 

[JBAirborne]

Here's something someone may know, I believe the two wires leading to the large temp sensor respond back to the ECM with OHMs, does anyone know what the readings should be for those two wires? Or do they send a certain amount of voltage? (5V/12V?). It's pretty much impossible for me to get a dealership to determine, I live 65 miles from the closest one and they're going out of business also so they limit their service and repair side to warranty work...

Or would it be easier for me to just run two brand new wires and resplice the connector? I'd rather test first though =/

 

[black_gst]

i think its a voltage thing... should be 5v on the hot side and then the signal going back to the ecu would be the altered one

 

[atruepretense]

Check your Wiring. You basically replaced every single part that could have thrown the P0125. If both your fans are on constantly, that means that you have a fault somewhere in the wires. Could be at the harness to the coolant temp sensor. Those damn things always break. On my car with a healthy working Engine coolant sensor, if I unplug it, both my fans run on. Since the ECU doesn't know the engine temp, it just begins a freakout moment to try and keep the car cool at all costs.


CHECK all the wiring to and from the sensor.